It is C. Nitrogen. Nitrogen is 78% of the atmoshere
 
        
                    
             
        
        
        
"REPRODUCTIVE ISOLATION" needs to occur for speciation to happen.....
        
             
        
        
        
Answer:
One-half of the daughters of an affected man would have this condition. 
Explanation:
Each daughter born to a woman that is positive for a dystrophin mutation on one of her two X chromosomes possess a 50 percent likelihood of possessing the mutation and also becoming a carrier. Carriers at times do not show the disease symptoms but may give birth to a child that has the mutation or the disease condition. DMD carriers do have a higher chance of cardiomyopathy.
A man with DMD cannot transfer the affected gene to his sons since he passes to his son a Y chromosome, not the X chromosome. But he will definately transfer it to his daughters, since each daughter possess her father’s only X chromosome resulting in the daughters being carriers. 
Hence, One-half of the daughters of an affected father and a carrier mother could have this condition.
 
        
             
        
        
        
Bloooooooooooon . , ,jh .
        
             
        
        
        
Answer:
D. A bicycle rusting.
Explanation:
A. is incorrect because tearing a piece of paper is a physical change, not a chemical change.
B. is incorrect because we are just heating up the object. That only changes how fast the particles are moving and the change in state of matter.
C. is incorrect because we are adding heat to change a state of matter (from solid to liquid) and it is a physical change.
Therefore, only D. is the correct answer. Iron rusts, and when it does, it chemically changes into an iron oxide (rust).